/* ==============================
   Global Styles
============================== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  background-color: #f9fafc;
  color: #222;
  font-size: 16px;
}

/* ==============================
   Header & Navigation
============================== */
header {
  background: #005fa3;
  color: #fff;
  padding: 15px 0;
  text-align: center;
}

header h1 {
  font-size: 1.8rem;
  margin-bottom: 6px;
}

nav {
  margin-top: 5px;
}

nav a {
  color: #fff;
  text-decoration: none;
  margin: 0 10px;
  font-weight: 500;
  transition: color 0.3s ease;
}

nav a:hover, nav a.active {
  color: #ffd95e;
}

/* ==============================
   Hero Section
============================== */
.hero {
  background: linear-gradient(120deg, #dbe9f4, #ffffff);
  text-align: center;
  padding: 60px 15px;
}

.hero h2 {
  color: #003b73;
  font-size: 2rem;
  margin-bottom: 10px;
}

.hero p {
  color: #333;
  max-width: 600px;
  margin: 10px auto 25px;
}

.explore-button {
  padding: 12px 25px;
  background: #005fa3;
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  border-radius: 6px;
  transition: background 0.3s ease;
}

.explore-button:hover {
  background: #004173;
}

/* ==============================
   Featured Book / Book Card
============================== */
.featured-books, .book-hero {
  padding: 40px 15px;
  text-align: center;
}

.featured-books h3, .book-details h3 {
  font-size: 1.6rem;
  color: #003b73;
  margin-bottom: 20px;
}

.book-card {
  background: #fff;
  border: 1px solid #e2e7ec;
  border-radius: 8px;
  max-width: 350px;
  margin: 20px auto;
  padding: 20px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.08);
  transition: transform 0.3s ease;
}

.book-card:hover {
  transform: translateY(-5px);
}

.book-card img {
  width: 100%;
  border-radius: 6px;
  margin-bottom: 15px;
}

.book-card h4 a {
  text-decoration: none;
  color: #005fa3;
  font-size: 1.1rem;
}

.book-card p {
  color: #444;
  font-size: 0.95rem;
  margin: 10px 0 15px;
}

/* ==============================
   Download Buttons
============================== */
.download-button {
  display: inline-block;
  background: #0078c2;
  color: #fff;
  text-decoration: none;
  padding: 12px 22px;
  border-radius: 5px;
  font-weight: 600;
  transition: background 0.3s ease;
}

.download-button:hover {
  background: #005fa3;
}

/* ==============================
   Book Details Section
============================== */
.book-details {
  background: #f3f7fb;
  padding: 40px 20px;
  border-radius: 8px;
  max-width: 900px;
  margin: 40px auto;
  text-align: left;
}

.book-details ul {
  list-style: none;
  margin: 15px 0;
}

.book-details li {
  margin-bottom: 10px;
  color: #333;
}

/* ==============================
   Categories & About Sections
============================== */
.categories, .about {
  background: #fff;
  border-top: 1px solid #e8ecf1;
  padding: 40px 15px;
  text-align: center;
}

.categories h3, .about h3 {
  color: #003b73;
  margin-bottom: 15px;
}

.categories ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
}

.categories li {
  margin: 10px 15px;
  padding: 8px 14px;
  background: #f1f5f9;
  border-radius: 5px;
  color: #222;
  font-weight: 500;
}

/* ==============================
   Footer
============================== */
footer {
  background: #003b73;
  color: #fff;
  text-align: center;
  padding: 15px;
  font-size: 0.9rem;
  margin-top: 40px;
}

/* ==============================
   Responsive Adjustments
============================== */
@media (max-width: 768px) {
  .hero {
    padding: 40px 10px;
  }
  .book-details {
    padding: 25px;
  }
  .categories ul {
    flex-direction: column;
  }
  .book-card {
    width: 90%;
  }
}